# Embedding VTK render in a dialog box in PyQT (i.e., not using QMainWindow)
**URL:** https://discourse.vtk.org/t/embedding-vtk-render-in-a-dialog-box-in-pyqt-i-e-not-using-qmainwindow/5492
**Category:** Support
**Created:** [April 4, 2021, 10:31am UTC](https://discourse.vtk.org/t/embedding-vtk-render-in-a-dialog-box-in-pyqt-i-e-not-using-qmainwindow/5492 "2021-04-04T10:31:11Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Vardonir](https://discourse.vtk.org/u/Vardonir)
#### Post date: [April 4, 2021, 10:31am UTC](https://discourse.vtk.org/t/embedding-vtk-render-in-a-dialog-box-in-pyqt-i-e-not-using-qmainwindow/5492/1 "2021-04-04T10:31:11Z")
I have a class that’s subclassed from QFrame that looks like this
```
class TestVTKinQFrame(QFrame):
def __init__ (self):
super(TestVTKinQFrame, self). __init__ ()
self.vl = QVBoxLayout()
self.vtkWidget = QVTKRenderWindowInteractor(self)
self.vl.addWidget(self.vtkWidget)
self.ren = vtk.vtkRenderer()
self.vtkWidget.GetRenderWindow().AddRenderer(self.ren)
self.iren = self.vtkWidget.GetRenderWindow().GetInteractor()
# Create source
source = vtk.vtkSphereSource()
source.SetCenter(0, 0, 0)
source.SetRadius(5.0)
# Create a mapper
mapper = vtk.vtkPolyDataMapper()
mapper.SetInputConnection(source.GetOutputPort())
# Create an actor
actor = vtk.vtkActor()
actor.SetMapper(mapper)
self.ren.AddActor(actor)
self.ren.ResetCamera()
self.frame.setLayout(self.vl)
# self.setCentralWidget(self.frame)
self.show()
self.iren.Initialize()
```
And I have a widget that uses this frame
```
class Widget(QWidget):
def __init__ (self):
super(). __init__ ()
# self.model = input_model
self.model = TestVTKinQFrame()
self._top_layout = QHBoxLayout(self)
self._top_layout.addWidget(self.model, stretch=85)
self.setLayout(self._top_layout)
```
where this widget is added to another layout in a QDialog.
But it keeps crashing for some reason.
If I define it as a class (that’s not subclassed from anything), the VTK render work, but it ends up being very small. Putting addWidget(stretch=90) does nothing for the size.
---
### Author:  [@dgobbi](https://discourse.vtk.org/u/dgobbi)
#### Post date: [April 6, 2021, 1:34pm UTC](https://discourse.vtk.org/t/embedding-vtk-render-in-a-dialog-box-in-pyqt-i-e-not-using-qmainwindow/5492/2 "2021-04-06T13:34:12Z")
Can you provide a complete (but small) program that demonstrates the problem?
One thing about your class doesn’t make sense. It’s a frame class:
```auto
class TestVTKinQFrame(QFrame):
```
But it seems to have “frame” as a member, which seems odd:
```auto
self.frame.setLayout(self.vl)
```
Why not `self.setLayout(self.vl)`?
---
### Author:  [@Edoardo\_Pasca](https://discourse.vtk.org/u/Edoardo_Pasca)
#### Post date: [April 9, 2021, 6:56am UTC](https://discourse.vtk.org/t/embedding-vtk-render-in-a-dialog-box-in-pyqt-i-e-not-using-qmainwindow/5492/3 "2021-04-09T06:56:33Z")
Hi
in my experience Qt crashes if something is not defined. In your snippet, it seems `self.frame` isn’t defined, but you try to dereference it, hence Qt crashes.
Also, as @dgobbi points out, your `TestVTKinQFrame` is a `QFrame` widget that you can put in other Qt widgets or windows.
I have a [similar setting](https://github.com/vais-ral/CILViewer/blob/master/Wrappers/Python/ccpi/viewer/QCILViewerWidget.py#L10): my VTK render window is inside a QFrame. I can then use that QFrame inside other Qt Widgets, like a QDockWidget or in a layout.
Edo